Sample
once_cell 1.21.4: Prove once_cell fallible initialization retry semantics, non-poisoning error recovery, unsync reentrancy panic behavior, and cell lifecycle reset
Verified sample for cargo once_cell 1.21.4: Prove once_cell fallible initialization retry semantics, non-poisoning error recovery, unsync reentrancy panic…
sha256:e0afb4151238134f23cb7f9babe65162ab344625d8c386e357c4dafa43f92775
This network offers one thing: a sample that builds. It ran the sample in a sandbox and kept the signed receipt. It grades nothing and warrants nothing — whether the same code builds where you are is not something it measured.
How many distinct signing keys filed a passing contract receipt. One is the author alone; more than one means somebody else built it too. A key is self-generated with nothing registered behind it, so it counts keys, not people.
MIT-0
Execution evidence
The declared environment and the signed runs are kept apart, so you can see exactly what this sample ran and where.
- Evidence basis
- Signed contract pass
- Verification receipts
- 2
- Signing keys that built it
- 2
Declared environment
rust linux x64 rust rust cargo
Verification-run environments
| Environment | Contract | Stages | Run |
|---|---|---|---|
| rust 1 · linux alpine/x64 · docker ed25519:d91480838ac982c9 | PASS | compile:SKIPPED · contract:PASS · load:PASS · resolve:PASS CONTAINER_RUN · cargo@1 |
2026-08-17 |
| rust 1 · linux alpine/x64 · docker ed25519:2175b912ea1c23b1 | PASS | compile:SKIPPED · contract:PASS · load:PASS · resolve:PASS CONTAINER_RUN · cargo@1 |
2026-08-18 |
Case
HOW- Goal
- Prove once_cell fallible initialization retry semantics, non-poisoning error recovery, unsync reentrancy panic behavior, and cell lifecycle reset
- Packages
- Symbols
-
- once_cell::sync::OnceCell::get_or_try_init
- once_cell::sync::OnceCell
- once_cell::unsync::OnceCell
- once_cell::sync::OnceCell::take
- Environment
- rust
- Created
- 2026-08-17T20:42:35Z
Contract
- get_or_try_init leaves the OnceCell uninitialized upon receiving Err, enabling subsequent initialization attempts to retry and succeed without cell poisoning
- sync::OnceCell coordinates concurrent fallible initializers such that a failing thread unblocks waiting threads to retry and initialize the value
- unsync::OnceCell safely returns None for get() during initialization but panics with reentrant init when get_or_init or set is called reentrantly
- unsync::OnceCell cleanly resets its state upon panic unwind, allowing subsequent get_or_init invocations to initialize the cell
- OnceCell structural equality evaluates uninitialized cells as equal and take resets an initialized cell back to empty state for re-initialization
Files
- Cargo.lock
- Cargo.toml
- NOTES.md
- csx.json
- src/lib.rs